Insulating pads and their manufacture

ABSTRACT

INSULATING PADS OF THE TYPE USED IN THE COVERING OF JOINTS ARE FORMED BY DRAPING A SHEET OF HEAT SHRINKABLE PLASTIC MATERIAL AROUND A TEMPLATE FORMED OF A BUNDLE OF RODS. SHRINKING OF THE SHEET MATERIAL FORMS A SHEATH HAVING THE DESIRED PAD SHAPE, THE SHEATH THEREAFTER BEING REMOVED FROM THE TEMPLATE, FILLED WITH INSULATING MATERIAL AND SEALED.

March 9, 1971 A. JEHIER INSULATING PADS AND THEIR MANUFACTURE 3 Sheets-Sheet 1 Filed Dec. 16, 1968 March 9, 1971 A.JEHIER INSULATING PADS AND THEIR MANUFACTURE 3 Sheets-Sheet 2 Filed Dec. us, 1968 March 9, 1971 A. JEHIER INSULATING PADS AND THEIR MANUFACTURE 3 Sheets-Sheet 5 Filed Dec. 16, 1968 3,568,396 INSULATING PADS AND THEIR MANUFACTURE Andr Jehier, 8 Rue Racine, 49 Angers, France Filed Dec. 16, 1968, Ser. No. 784,139 Claims priority, application France, Dec. 28, 1967, 134,127 Int. Cl. B65b 43/08 U.S. CI. 53-29 7 Claims ABSTRACT OF THE DISCLOSURE Insulating pads of the type used in the covering of joints are formed by draping a sheet of heat shrinkable plastic material around a template formed of a bundle of rods. Shrinking of the sheet material forms a sheath having the desired pad shape; the sheath thereafter being removed from the template, filled with insulating material and sealed.

BACKGROUND OF THE INVENTION (1) Field of the invention The present invention relates to a process for the production of pads for the thermal and sound insulation of aircraft cabins or the like. More specifically, the present invention is directed to insulating pads consisting of an impermeable case of light weight, the case containing an appropriate insulating material such as, for example, glass fibres. Accordingly, the general objects of the present invention are to provide new and improved methods and apparatus of such character.

(2) Description of the prior art While not limited thereto in its utility, the present invention is particularly well suited for the production of insulating pads intended to cover joints or the like. As a rule, the insulating pads produced until now are flat. Accordingly, when the previous pads were pressed against curved surfaces, for example on being secured Within an aircraft, deformations accompanied by local compressions of the insulating material were caused thereby reducing the effectiveness of the material.

In vie-w of the ever increasing speed and cruising altitude of aircraft, a need arises to improve the thermal and sound insulation properties of these pads.

SUMMARY OF THE INVENTION It is an object of the present invention to produce insulating pads, by a simple process, the pads thus provided being endowed with the curvature of the surface intended to receive them.

To this end, the process according to the present invention comprises winding a sheet of a plastic material of such nature as to undergo shrinkage under application of heat, for example, on a former or template possessing the shape of a joint, section or the like which is to be faced or lined. The two edges of the said sheet are thereafter joined to each other and the assembly is exposed to the action of the particular agency apt to cause the shrinking of the sheet. The shrunken sheet, which has been contracted to the shape of the template, is removed from the latter by sliding it off the template and both extremities of the tubular sheath or case thus formed are sealed by means of an end-piece of plastic sheeting joined to the corresponding extremity of the said sheath. Finally, the said sheath is slit longitudinally, filled with insulating material, and the incision is resealed.

Thanks to the above-described process, insulating pads may be produced in advance to match the shape of the joints, sections or the like, on which they are to be installed. Accordingly, the pads cannot develop any folds i d States Patent on being installed and thus retain their full insulating capacity.

In accordance with a preferred embodiment, the sheeting comprises a plastic substance weldable by means of high-frequency currents such as, for example, shrinkable polyvinyl chloride or a complex of polyvinyl chloride and another shrinkable plastic substance, such as a polyester for example. The fastening of the said end-pieces as Well as the final resealing of the sheath may thus be performed by means of high-frequency currents thereby eliminating the need for any conventional form of solidification by means of some glue. As is well known, no glue can be considered to be entirely fireproof.

The present invention also relates to equipment for the application of the above-described process, such equipment being characterized in that it comprises a template of bow shape consisting of an assembly of metal rods possessing the curvature of the joint, section or the like which is to be covered by the pad to be produced. The

said metal rods are positionable in such manner relative to each other as to reproduce the required section in the said pad, the rods having their extremities fastened to the corresponding two extremities of a bearer in such manner that they may be released again at one end at least.

Finally, the present invention relates to the insulating pads produced by the application of the process and/or by means of the corresponding equipment.

BRIEF DESCRIPTION OF THE DRAWING The present invention will now be described with reference to the accompanying drawing wherein like reference numerals refer to like elements in the various figures and in which:

FIG. 1 is a perspective view of a template which may be employed to produce a first embodiment of an insulating pad in accordance with the present invention;

FIG. 2 is an exploded view, in perspective, on an enlarged scale, of the extremity of the template of FIG. 1;

FIG. 3 shows an enlarged scale cross-sectional view taken along the line IIIIII of FIG. 1;

FIG. 4 illustrates an insulating pad element produced with employment of the template of FIGS. 1 to 3;

FIG. 5 is an illustration, in perspective, of a modified form of the pad element of FIG. 4; and

FIG. 6 is a cross-sectional view, analogous to that of FIG. 3, showing a template for use in production of the pad element of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT The complete template shown in perspective in FIG. 1 is intended for use in the production of insulating pad elements analogous to that shown in FIG. 4. In essence, the said template consists of an arcuate bundle 1 of metal rods having both its extremities secured to a bearer 2. The bundle 1 of metal rods possesses the overall curvature of the section or joint intended to be covered by the pad which is to be produced on the template.

Bundle of metal rods 1 comprises a first set of rods 3, 4, 5, 6, 7, 8 and 9, also apparent in FIGS. 2 and 3, which are intended to act as bearers for a sheet of plastic material 12 to form the external shape of the pad section to be produced. Bundle 1 also includes a second set of rods 15, 16 and 17, which may best be seen from FIG. 2 and which are intended to act as bearers for the part of the plastic material sheet to be situated within the said section.

One extremity of each of the rods is anchored in a metal plate 21 (FIG. 1) which forms part of the bearer 2 and which is coupled rigidly to a bar 22 of the said bearer. The other extremities of the metal rods fit freely into blind holes wrought in another plate 23. Plate 23 is fastened in releasable manner on the other extremity of the bar 22, for example by means of a nut 24 screwed on one extremity of the bar 22, bar 22 being necked down and screwthreaded for this purpose. As an example, FIG. 2 shows a blind hole 26 receiving the extremity of the metal rod 8 when the releasable plate 23 is installed on the bearer 2.

In order that the template may possess adequate rigidity, the metal rods are appropriately braced against each other. To permit the template to be employed, the external rods should, however, be interconnected by means of staying plates 28 which are distinct from the staying plate 29 (FIG. 3), plates 29 interconnecting the inner rods 15, 16 and 17. Each rod is preferably connected to the staying plates by welding or brazing.

The staying plates 28 for the outer rods possess an excision 31 corresponding to the outline of the joint or section to be lined or faced. Excision 31 allows the placing in position of the sheet 12 of plastic material (FIG. 3). The edges of all the staying plates are slightly set back from the outer surface of the rods they secure, so as not to impede the slipping off of the sheet of plastic material when the same is to be removed from the template.

The following procedure may be applied to produce an insulating pad of the kind illustrated in FIG. 4.

A sheet of plastic material of appropriate nature is wound around the rods of the template as shown in FIG. 3, and two extreme edges of this sheet are joined together by any appropriate temporary means, for example by means of clips 34. The template thus covered with the sheet of plastic material is exposed to the action of heat, for example at a temperature of the order of 220 Centigrade, either in a stove, or by immersion in a hot liquid if the configuration of the sheet is especially involved. Accordingly, the sheet which, on being placed in position, formed creases in the portions situated closest to the center of the overall radius of curvature, is retracted (shrinks) onto I the template and assumes a smooth outline.

A slit is cut in the sheath close to the line of clips 34. The releasable plate 23 is removed after unscrewing the nut 24, and the sheath formed is removed by being slipped along the template. It is to be noted that the particular shape of the staying plates renders this removal operation possible. Both end extremities of the sheath, the sheath being indicated at 36 in FIG. 4, are sealed off by means of small pieces of analogous plastic sheeting 37. End sheets 37 are welded, for example by means of high-frequency currents, on the edges of the corresponding extremity of the sheath 36, these edges having been slightly opened outwards by deformation. The sheath is next filled with the insulating material selected, for example glass fibres, and the sheath is resealed by means of a strip 38 (FIG. 4) consisting of plastic sheeting of analogous nature. As with end cover sheets 37, strip 38 is welded by means of high-frequency currents along the two open and outwardly bent edges of the sheath. These two longitudinal welding seams are indicated at 41 and 42 in FIG. 4.

The appearance of the resulting pad element is as shown in FIG. 4. In its final form, the configuration of the pad element corresponds to the shape of the joint or section it is intended to face or line, all its surfaces being satisfactorily smooth.

FIG. illustrates a modified form of pad element; the pad of FIG. 5 resembling that of FIG. 4 but differing from the latter in that its cross section is rectangular instead of being trapezoidal. The pad of FIG. 5 is also distinguished by the fact that, along its two lateral surfaces, it possesses two longitudinal connecting fins 46 and 47 for installing two pads between joints. A second pad in such an installa tion is shown partially by broken lines at 48 in FIG. 5. It is to be noted that the two welding seams 41 and 42 form connecting fins or webs which cooperate with fins 47 and 46 respectively.

FIG. 6 illustrates the cross section of a template of the same kind as that of FIGS. 1 to 3, but additionally comprising three complementary metal rods 51, 52 and 53 at one side, and three analogous complementary metal rods 54, 55 and 56 at the other side. The complementary sets of rods form lateral folds of the sheet 12 of plastic material intended to produce the two fins 46 and 47 of the pad of FIG. 5. The fins may, for example, be formed by a highfrequency welding operation applied through the two thick nesses of these folds.

The present invention is not limited to the methods of operation and the embodiments described and illustrated herein, and modifications may be incorporated without exceeding the scope of the invention. For example, instead of a complex of plastics material, a pure vinyl chloride shrinkable by the action of heat may contingently be employed. Also, another plastic material which may be caused to contract by the action of agencies other than heat could alternately be employed, the applicable principle consisting of positioning the sheet of plastic material in the required shape on a template and of causing its contraction to eliminate the folds which may be formed upon placing this sheet in position.

Accordingly, it may be seen that the present invention has been disclosed by way of illustration and not limitation.

What is claimed is:

1. A process for the manufacture of an insulating pad comprising the steps of:

positioning a sheet of shrinkable plastic material on the exterior of a three-dimensional template, the template defining the desired pad shape;

joining two oppositely disposed edges of the sheet;

causing shrinkage of the sheet whereby the sheet conforms to the shape defined by the template and forms a tubular sheath thereabout;

removing the tubular sheath from the template;

filing the interior of the sheath with an insulating material; and

sealing the ends of the sheath.

2. The process of claim 1 wherein the step of filing the interior of the sheath .with insulating material comprises:

cutting a longitudinal incision in the sheath;

inserting the insulating material through the incision;

and

sealing the incision.

3. The process of claim 2v wherein the ends of the sheath are sealed prior to cutting of the'longitudinal incision.

4. The process of claim 2' wherein the step of joining the oppositely disposed edges of the, sheath comprises: temporarily clamping the edges together.

5. The process of claim 1 wherein the step of sealing the ends of the tubular sheath comprises: fusion bonding sheets of plastic material to the ends of the sheath.

6. The process of claim 3 wherein the step of sealing the ends of the tubular sheath comprises: fusion bonding sheets of plastic material to the ends of the sheath.

7. The process of. claim 3 wherein the steps of sealing the ends of the sheath and sealing the incision comprise: fusion bonding sheets of plastic material to the sheath.

References Cited 7 UNITED STATES PATENTS 2,890,489 6/1959 Noyes et al. 18 45 2,845,658 8/1958 Knibb 18 45 3,306,795 2/1967 Morse 264342X THERON E. CONDON, Primary Examiner H. M. CULVER, Assistant Examiner 

